[tracing] Introduce "allowed_dump_modes" for memory dump config

content/browser/tracing/background_tracing_manager_impl.cc

Index: content/browser/tracing/background_tracing_manager_impl.cc
diff --git a/content/browser/tracing/background_tracing_manager_impl.cc b/content/browser/tracing/background_tracing_manager_impl.cc
index 610b01881c2570af6b78c2ead730d16f4c2d7571..536624022f28758557e30fe643acbf22a8c0e24a 100644
--- a/content/browser/tracing/background_tracing_manager_impl.cc
+++ b/content/browser/tracing/background_tracing_manager_impl.cc
@@ -47,8 +47,6 @@ void RecordBackgroundTracingMetric(BackgroundTracingMetrics metric) {
 }
 
 // Tracing enabled callback for BENCHMARK_MEMORY_LIGHT category preset.
-// TODO(ssid): Remove this when background tracing supports trace config strings
-// and memory-infra supports peak detection crbug.com/609935.
 void BenchmarkMemoryLight_TracingEnabledCallback() {
   base::trace_event::MemoryDumpManager::GetInstance()->RequestGlobalDump(
       base::trace_event::MemoryDumpType::EXPLICITLY_TRIGGERED,
@@ -409,6 +407,12 @@ void BackgroundTracingManagerImpl::StartTracing(
                            BENCHMARK_MEMORY_LIGHT) {
     // On memory light mode, the periodic memory dumps are disabled and a single
     // memory dump is requested after tracing is enabled in all the processes.
+    // TODO(ssid): Remove this when background tracing supports trace config
+    // strings and memory-infra supports peak detection crbug.com/609935.
+    base::trace_event::TraceConfig::MemoryDumpConfig memory_config;
+    memory_config.allowed_dump_modes =
+        std::set<base::trace_event::MemoryDumpLevelOfDetail>(
+            {base::trace_event::MemoryDumpLevelOfDetail::BACKGROUND});
     trace_config.ResetMemoryDumpConfig(
         base::trace_event::TraceConfig::MemoryDumpConfig());
     tracing_enabled_callback =